Method of and apparatus for preventing the condensation of moisture on the exterior surface of refrigerator cabinets



March 19,' 1929. Y

METHOD OF AND APPARATUS FOR PREVENTING THE CONDENSATION OFv MOISTURE ONTHE EXTERIOR SURFACE OF REFRI'GERATOR CABINETS mal IIIHIIHIHIIHW-w/T/VESS March 19, '1929. Y y' .f A, L, LAMBER'I" 1,705,928 l METHOD 0FAND APPARATUS FOR PREVENTING THE coNDENsATIoN oF MOISTURE on THEEXTERIOR SURFACE 0F REFRIGERATOR cABINETs Filed lay 20. 1927 2 Sheets-Sheet 2 6 .5 B30 J4 .I7 97 'si Y'fa 'f/ J6 A l! l w/TA/Ess .Bf m4, Aw17* OHNEY Patented Mar. 19,` 1929. l

UNITED STATES PATENT o1=1=1cE.v` ALBERT L. LAMEERT, OF NARBERTH BOROGH,PENNSYLVANIA, ASSIGNOR TO HEINTZ l MANUFACTURINGCOMPANY, A CORPORATIONOF PENNSYLVANIA. v

I METHOD F APPARATUS FOR PBEVENTING' THE CONDENSATION OF MOISTURE ON THEEXTERIOR SURFACE OF REFRGERATOR CABINETS.

Application led May20, 1927. Serial No. 192,861. e

It is Well known that asthe temperature within 'a refrigerator isconsiderably below that of the surrounding atmosphere, there is acontinual transfer' `of heat from the walls 5 of the refrigerator to theinterior thereof, with the result that the walls are reduced intemperature and maintained below that of the surrounding atmosphere.lVhen the outer surface of the refrigerator cab-inet is lowl0 ered intemperature to or below. the dewpoint temperature of thev surroundingat` mosphere the latter becomes more or less dehydrated through thecondensation and deposit of moisture or dew on the relat1vely coolsurface.

The condensed moisture collected on the outer surface of the cabinet isunsightly and obviously objectionable in theuse ofzthe refrigerator. Asit accumulates it runs down the outer surface of the cabinet and dripsupon the floor, rendering the lattercontinually damp and sometimesmaintaining a pool there, which is, of course, unsanitary and untidy andtends to rot the/Hoor as time goes on. Furthermore, tlie condensationinjures the finish applied to the exterlor of the cabinet and not onlymars its appearance, but tends t'o warp or rot the wall if the outersurfacev is of wood or other material similarly aected by moisture, orto cause it to rust if iliade of metal. A. I

The amount of'such condensation per unit of area depends upon theatmospheric condition and upon the temperature of the outer surface ofthe-cabinet due tothe transfer or leakage of heat from the walls of thecabinet-'to'- the interior of lthe refrigerator, the latter factor beingin turn dependent (disregarding the so-called skin effect and possibleheat losses through radiation) upon the difference in temperaturebetween the interior of the refrigerator and the surrounding atmosphere'and upon the thermal conductivity of or rate -of/ heat transfer' throughthe refrigerator walls. y As to the atmospheric.condition both hu-`midity and temperature are important. The higher the humidity therelatively higher the dew-point, and the more readily the condensationforms lsince less heat transfer Y through the walls will reduce thetemperature ofl the outer surface lof the cabinet to the dew-point. .Ahigher percentage of humidity also renders the condensation moreprofuso. On the other hand, a higher atmospheric temperature ives ahigher saturation point, making possi le a larger proportion of aqueousvapor in the air. A relatively hlgh temperature also increases the usualtemperature difference between the atmosphere and the interiorof therefrigerator y within the refrigerators than ice does, and

hence their introduction has increased the tendency toward the formationof condensatlon on the exterior of the cabinets and has rendered the4problem more acute.

The thermal conductivity of refrigerator walls varies, of course,according to the material or materials of which they are constructed andthe thickness thereof. But in every mstancethereis necessarily someheat.

transfer through the walls as perfect insulation is impossible.Furthermore, there are vpractical'difficulties in obtaining the maximuminsulating efficiency, particularly in refrigerators of the domestictype, since the element of expense limits both the character 'and thethickness of the insulating materials which can be used in producing asaleable article, and furthermore, since the walls can-- not be toothick without eitherencroaching unduly on the space required forrefrigerating purposes or else rendering,thepcabinet too bulky andcumbersome. Where the wallsl are constructed, as in ordinary cabinets,with their outer surfaces of wood, the objectionable condensation formsunder certain of the above mentioned conditions, but wherey the outersurfaces are of metalas in the modern cabinets the condensation has beenfound to be particularly troublesome.y

These Various factors or conditions enter- :ing into the formation ofthe condensation cannot be controlled or eliminated as a practical meansofeffecting a solution of the problem.

An object ofthe resentinvention is to l provide a method of effectivelypreventing 5 the formation of such condensation on the exterior surfaceof a refrigerator cabinet Inotwithstanding the existence of theaforesaid factors or conditions and the degree in which the are present,and without inter vfering wity the efficiency of the refrigerator,

yas well as on the stationary walls thereof.

A further object'jof the invention is to provide an apparatus forcarryingout this process which yoperates positively and auto- Ymatically and without adjustment or atten- 't1on, which 1s simple 1nconstruction, has no moving parts, and is not likely to get out oforder, and`which adds but little to the cost of the usual 'refrigeratorstructure.

With-these and other objects in View, the

.2K5 invention comprises the several stepslv and the relation thereof toeach other which will be exemplified in the hereinafter disclosedmethod, and the Ifeatures of construction, combinations of` elements andarrangements 30 of parts which will be exemplified, in the ap aratushereinafter set forth.

eferring to the accompanying drawings in which similar referencenumeralsindicate f similar parts throughout the several views- Fig. l.isa diagrammatic view illustrating the operation of my method forpreventing the condensation of moisture on e exterior walls of therefrigerator cabinet;

Fig.l 2 1s a transverse vertical section of @D one embodiment of arefrigerator cabinet for carrying 'outthe process above referred to, thesection being talren 4on the line of 2 2 of Fig. a; 1

Fig. 3 is a horizontal'section thereof, the

section being taken on` the line'o'f 3-3 of Fig. it; v

- Fig 4l is a vertical section fromfront to rear, the section beingtaken `on the line of 4-4 of Fig. 2; i

0 7 Fig. 5 is a snnilar view taken on vthe line of 5 5 oflig 4f; and p pf Fig. @isan enlarged sectionalViewv show v lng the doorky structure. f

tion and deposit of moisture or. dew 9 on the exterior surface' of thelwall .of a refrig- -erator cabinet, l create .and maintain within, andin spaced relation to, such wall,l a .zone

' 60 of temperature at or below the, dew-point of the normal atmos hereoutside of, or surrounding, the cabmet. Such zone may be formed, forinstance, by the wall of an i `innerrefrigerating compartment, which is@6.5 cooled by'any suitable refrlgerating (means and the temperature ofwhich, is usually maintained below the dew-point of the nor- -malatmosphere outside of the cabinet. l. admit air from the outsideatmosphere to the inner side of the cabinet wall to fornrand maintain allayer of air which covers the inner surface thereof, and which isinteraA certain lowering of the temperature of.

lthe layer, increase its density and cause it to descend, sweepdownwardlyover the inner surface of the cabinet wall and pass at itslower end into the outside atmosphere, while additional volumes of airare simultaneously drawn in from the outsidel atmosphere at 'and follow(the upper end of the descending layer. As the layer passes downwardlyalong the zone of lower temperature it is cooled thereby Vmore and more,until it finally escapes.

I regulate the passage of the layer of air` into the, outside atmosphereso that it es-4 capes before becoming lowered in tempera.

ture 'to the point of reducing,`-by carrying off heat from the wall ofthe cabinet,the temperature of the outer surface of the cabinet wall tothe dew-point of the-outside atmosphere. rihis is an important step inythe process and is effected by suitably. roportioningl the thickness ofthe layer o air ieu to the height of vthezone of relatively lowtemperature along which it travels, and also to the heat transfer fromthe layer to .the

zone, which latter factor is dependent, when l the zone is inthe form ofa wall of an inner refrigerating compartment, upon thethermalconductivity ofsuch wall, and upon the difference between the normalItemperature llO of the layer as'itris admitted from the outsideatmosphere, and the temperature within the inner refrigeratmgcompartment. he

height of the wall of the inner refrigeratingr compartment and' also thethermal conductivity thereof can, of course, readily be determined.However, there may be consid- 1 erable. variation from time to time inthe i, lin carrymg out `the present embodiment 5 5 ofmy methodofpreventing the'condensaf normal temperature of the layer of 'air (whichcorresponds with the temperature of the outside atmosphere), and\-th`etemperature maintained within the inner refrigerating compartment- Bytaking` the probable' -,of the theory of operationof this method, itV

-is believed that the portion of the layer of air coming in contact withthe zone as the air is admitted from the outside atmosphere, is loweredin temperature and 'forms a stratum which is cooler than the stratum inf contact with the inner surface of the cabinet wall. The cooler stratumdescends by reason ofits increased density and as it flows downwardlyalong and in Contact with the zone is cooledthereby more and more andbecomes gradually thicker and flares downwardly andv outwardly, whilethe warmer ystratum is correspondingly, gradually reduced in` thicknessand tapers from the upper and to the lower end of the layer.

lVhile there vmay be no actual sharp line of division between rthe twostrata, ythey may be considered as divided, atleast theoretically,valonga plane extending obliquely between the zone and the cabinet wall andin' togetherat the lo/wer end of the layer intol the outside atmosphere.By 'suitably-pra portioning the thickness of the layer, as hereinabovedescribed, the plane of division will pass from end to end of'. thelayer without touching the cabinet wall, and the inner surface of thecabinet -wall will be at all times entirely covered by the warmerstratum of the layer of air, the temperature of which stratum issubstantially the same asr the outside atmosphere. Under thesecircumstances .there is little, if any, heat transfer from the cabinetwall to the layer, andtherefore the lowering of the temperature oftheouter surface of the cabinet wall to the dew-point of the outsideatniosphcre is avoided and the formation of condensation thereon iseffectively prevented.

Of course, itis not desired to have 111e, layer of' air any thicker thannecessary since that involves either adding to the bulk of the cabinetor encroachiug on the available space therein, and might also interferewith the drawing of the warmer stratum downwardly with the coolerstratum the latter de scends. But even if the layer is reduced inthickness so that the plane of division between the strata intersect-sthe cabinet wall and the cooler stratum comes in contact with the innersurface thereof, the `method is nevertheless operative so long asthelayer "descends and escapes into the outside atmosphere before anyportion thereof in contact with the inner surface of the cabinet wall tothe point of reducing,-by carrying off heat from the wall,-thetemperature of the outer surface of the cabinet wall to the dew-point ofthe outside atmosphere.

It will be apparent that this method may be employed in connection withthe respective walls of'a refrigerator cabinet, partielllai-ly theupright walls, and with the door or movable wall as well as with thestations ary walls thereof, that it will prevent condensation on theexterior surface of the cabinet notwithstanding the existence of' thebecomes lowered in temperature by the zone beforeinentioned factors andconditions entering into its formation, and that the operation of themethod will inno wiseinterfere with the efficiency of the refrigerator.

Referring to the present embodiment of the' apparatus for carrying outmy method, the re rigerator cabinet comprises an exterior casing 1 andan inner refrigerating compartment 2 mounted therein as hereinafterpointed out.

The casing is preferably, although not necessaril made of heavy sheet.metal, the outer surface of 'which is painted, lacquered, enameled orotherwise given an attractive finish. It has aback wall 3, side walls 4,and a top wall 5, the front being open. ,The side and top walls maybeformed from one piece of metalwith flanges 6 along their Arear edges towhich the back wall 3 is rigidly secured, as by screws or rivets 7.

A pan Sis arranged within and extends across the casing below therefrigerating compartment 2, and is suitably fastened,- as at 9, to theback wall 3 and .side walls 4. A drain pipe l() may lead from the panand in the present instance is shown as passing outwardly through theback wall 3, the bottom of the pan being inclined toward the drain, soas to cause any -water collecting in the pan to pass off' therethrough.

The casing preferably extends downwardly below the pan to provide acompartment 1l beneath the same for housing the mechanical unit (notshown) employed when the refrigerator is cooled mechanically. In suchinstance a bottom 12 for .this coiiipartn'ient is secured across thelower end of the casing.

A frame of'wood or other suitable material is mounted within the openfront of thel casing and comprises sides 13 extending substantially thefull height of' the casing, aii upper cross-bar or top 14, and a lowercrossbar 1 5 located above but adjacent to the pan-8. The uppercross-bar 14 of this frame is secured by screws 16 or the like to afacing 17 which depends from the top wall 5, turns inwardly beneath thecross-bar and substan` tially conceals the latter from View. The sides13 are secured, as at 18, to similar facngs 19 extending laterally andinwardly from the side walls 4 of the cabinet. A facing covers the frontsurface of the lower cross-bar 15 and extends downwardly therefrom andis turned rearwardly under` and supports the front of the pan 8.

-The inner refrigerating compartment 2 is box-like in form, is open atits front, and is supported by, and suitably secured along its frontedges to, the frame. `While this compartment may be of any appropriateconstruction, it consists in the present instance of nested, metallicshells 21 and22, with suitable insulating material 23 interposedtherebetween, the -shells being fastened, as at 24, to the -sides 13 andupper and lower cross bars 14 and 15 of the frame. The bottom of thecompartment is valso supported upon and in spaced relation to the pan 8by means of a plurality of inter osed blocks 25 arranged so as not tointer ere with the free drainage of the pan to the pipe 10. A. chamber26 is thus provided between the' compartment and the pan.

The compartment 2 is otherwise spaced yfrom the casing 1 so as toprovide intervening air chambers 27 between back and sides of thecompartment, and the corresponding back wall 3 and side walls Ll, and anupper air chamber 28 between the top of the compartment and the top wall5. The chambers 27 communicate attheir upper ends with the chamber 28and at their lower ends with the chamber 26.

Openings or louvres 29 are formed in the back wall 3v and the side wallsY4c adjacent the upper and lower ends, respectively, of

the chambers 27, whereby to admit air freely fromthe outside atmosphereand permit itl to circulateI therethrough. There may be one or aplurality of openings or louvres 29 at each end, but in either instancethey extend across the correspondingwall ofv the casing forsubstantially the full width thereof and their total area is preferablyapproximately equal to the cross-sectional -area ofthe adjacent lchamber27 and ,to the total area of the openings or louvres at the opposite endof such chamber.

To-admit air from the outside atmosphere' to the upper chamber 28, oneormore openings 30'are formed in the top wall 5 substantially centrallythereof. In connection with this chamber 28 it is to be noted that'thetop of the refrigerating compartment 2 is inclined downwardly from-front to rear (as shown in Fig. 4) for a purpose to be hereinafterpointed out.

Mounted on the frame at the front of the refrigerator cabinet is a doorconsisting of an inner wall 31 and an outer wall 32, the former beingheat insulated as indicated at 33 and Vbeing adapted to close snuglyagainst a suitable seat -or gasket 34 surrounding the doorway. The outerwall 32 has a suitable nish a plied to its outersurface and is supporte1n spaced relation to the inner wall 31 so as to provide one or moreintervening air chambers 35. In the present instancethe su porting meansconsists of a plurality o vertically disposed spacing strips 36, two ofwhich are interposed between the walls adjacent the side edges thereof,and another ofwhich located intermediately of these two. Two chambers 35are thus provided and' are similarly opentop and bottom to 'admit airfrom the outside atmosphere and permit it to circulate therethrough.

Adjacent the lower ends of the chambers 35 and beneath the outer surfaceof the inner Wall 31, is a trough or gutter 37 extending alone' andcarried by the lower crossbar 15 ofa the frame. This trough drains to,an outletpipe or spout 38 vwhich passes through the cross-bar 15 anddischarges into the pan 8.

A cooling `element 39 is contained within the refrigerating compartment2 and lowers the temperature therein and usually maintairts the samebelow the dew-point. of the normal outside atmosphere. Thiselement maybe in the form of the usual brine tank or other cooling unit of amechanical cooling system, or in the form of ice.

In the operation of the apparatus, the

layers or columns of air within the respective chambers 27 normallydescend therein through the cooling action lof the corresponding wallsof the refrigerating chamber 2 and continually pass into the-outsideatmosphere through the lower.i openings or louvres 29, while additionalVolumes of air are simultaneously drawn int-o the chambers through theupper openings or louvres 29. By having the total areas of the upper andlower louvres of each chamber substantially equal to each other and tothe crosssectional area of such chamber thecirculation of air is freeand unobstructed, and by having the openings or louvres 29 extendtransversely for substantially the full width of the wall of the casingthe circulation Will be substantially 4uniform across the full width ofeach chamber. O11 account of the communication between each of thechambers 27 and the upper air chamber 28 the` descending layers o airinthe former also serve to draw the layer of air downwardly from thelatter and cause air from the outside `atmosphere to be simultaneouslyad- .mited through the openings 30 in thev top wa l 5.

various air chambers is-determined by the spacing between the outercasing and the inner refrigerating compartment, and is ulate the passageof the layers of air into the The thickness of the layers of air inthese outside atmosphere so that they escapebe'- A fore becoming loweredin temperature by contact with the walls of the inner refrigeratingcompartment to the point of' reducing,-by carrying off heat from thewalls of the vcasing,--the temperature of the outer. surface of thecasing to the dew-'point of the outside atmosphere. The samejactiontakes place in connection with the air chambers 35 located between theinner land outer walls of the door. As a result, the condensation ofmoisture or dew on the exterior surface of the casing is effectivelyprevented, and this applies to the door kas well asto'the station-y arywalls.

Any condensation vthat does form occurs on the outer surface of thewalls ofthe inner refrigerating compartment and the outer surface of theinner wall of the door, all of which are hidden from view and are notrequired to take' an attractive'iinish and hence may be suitablyconstructed or treated to withstand moisture,-without detracting.

from the :appearance of the refrigerator Moreover, such condensationcollecting on the side and back walls of the re'- frigerating chamberruns ldown -the same into thev chamber 26`below `the refrigerating.

compartment and is received in the pan 8, from which it is dischargedthrough thev drain-pipe l0. Moisture condensed on the top wall of therefrigerating lcompartment will flow rearwardly by virtue of theinclined disposition thereof, above pointed out, and hencewill run 'downthe rear wall of the compartment into the pan.` The trough or vgutter 37receives the condensed moisture which dri s from the outer surface ofthe inner wall o the doorand carries the same off through the pipe 38 tothe pan.

It is to be noted that none of the air chambers are in communicationwith the interior of the refrigerating compartment and -that theadmissionv of air thereto from the outside atmosphere and itscirculation thereu' through in no wise interferes with the efiir 'ciencyof thc refrigerator; the apparatus opcrates positively andautomatically, 'and without adjustment or attention, is simple inconstruction, has no moving parts, and is not likely to get out oforder,and involves but little addition to the cost of the usualrefrigerator structure.

lVhile in the present embodiment of the apparatus chambers surround theinner'refrigerating compartment on all sides, the chamber at the top ofthe cabinet may be omitted,'as well as one or more of the other chambersif not required in a given instance. Where a mechanical unit is notemployed-in cooling the refrigerator, the compartment therefor in thelower portion of the cabinet may be used for general storage purposes oromitted altogether.

Furthermore, it is to be understood that the location and arrangement ofthe openings or louvres may be varied, that the drain may be omitted,and that various other changes may be made in the method and -apparatusherein disclosed without departing from the spirit of the invention asdefined in the appended claims.

Having thus described my invention, I claim and desire to protect byLetters Patent of the United States- 1. The method of preventingcondensation on the exterior surface of the wall of a refrigeratorcabinet, which consists in causing a layer of air from the outsideatmosphere to sweep downwardly across the inner surface of the wall byexposing the layer to. a zone of lower temperature within the wall, andcausing the layer to pass into the outside atmosphere beforey becominglowered in temperature to the point of. reducing, by carrying off heatfrom the wall, the temperature of the outer surface of the wall to thel`dew-point of the outside atmosphere.

2. The method of preventing'condensation on the exterior surface of the.wall of a refrigerator cabinet, which consists in admitting air fromthe outside atmosphere to 'form a' layer covering the inner surface ofthe wall and in free communication adjacent its upper and lower endswith the outside atmosphere, cooling such layer from the side thereofremote from the wall and' therebycausing the layer to descend and passinto the outside atmosphere at its lower end and simultaneouslyvdraw inadditional volumes of air at its upper end, and causing the layer of airto pass into the atmosphel'e before the 100 portion thereof in contactwith the wall becomes lowered to the dew-point temperature of theoutside atmosphere.

3. The method of preventing condensation on th'e exterior surface of thewall of a re- 105 mosphere to follow the upper end of the descendinglayer, and causing the descending layer to pass into the outsldeatmosphere at its lower end before the portion of the layer in contactvwith the inner surface of the wall is cooled to the dew-point of theoutside atmosphere.

4. The method of preventing condensation on the exterior surface of' arefrigerator cabinet, which consists in causing a layer 125 of air to beinterposed between the wall of `an inner refrigerating compartment andthe wall of a surrounding casing and in free `communication vadjacentits top and bottom with the .outside atmosphere, cooling the layer ofair by contact with the wall of the refrigerating compartment andthereby causing the layer to descend and drawin additional volumes ofair from the outside atmosphere to follow the upper end of thedescending layer, and causing the descending layer to pass at its lowerend into the outside atmosphere before becoming lowered in temperatureto the point of reducing, by carrying off heat `from the casing wall,the temperature of the outer-surface of such wlzill to the dew-point ofthe outside atmosere. v

l- 5. In a device of the character described, the combination of innerand outer walls y spaced apart with an intervening air chamber, thechamber having vertically spaced openings leading therefrom andcommunicating with the outside atmosphere, and

refrigerating means within 'the inner wall cooling the same to or belowthe dew-point temperature of the outside vatmosphere and thereby causingair from the outside atmosphere normally to circulate continuallydownwardly through thel chamber, to prevent the condensation of moistureon the exterior of the refrigerator cabinet.

6. In a device of the character described,

for preventing the condensation of moistureon the exterior of arefrigerator cabinet` the combination of inner and outer walls spacedapart wlth an intervening air chamber, the chamber having verticallyspaced openings leading'therefrom and Xcommuni- A eating with theoutside atmosphere, and

means within the inner wall cooling the same to the dew-pointtemperature of the outside atmosphere and thereby causing air from theoutside atmosphere to circulate downwardly through the chamber, thespacing between said walls bein proportionedE to the distance the airtrave s along the inner wall and to the heat transfer from the air tosuch inner wall. i L v 7. In av device of the character described,

for preventing the condensation of moisturel on the exterior of arefrigerator cabinet, the combination of inner and outer walls spacedapart with an intervening air chamber, the chamber :having verticallyspaced openings leading therefrom and communieating with the outsideatmosphere, and means within the inner wall cooling the same to thedew-point temperature of the outside atmosphere and thereby. causing airfrom the outside atmosphere normally to circulate downwardly throu h thechamber,l the areas of said o enings to each ot er and Vto thecross-sectional area of the chamber'. i v c y 8. In a device of thecharacter described, for reventing the condensation of moisture on t eexterior of a refrigerator cabinet, the combination of inner and outerwalls spaced apart with an intervening air chamber, the

ltially the full width thereof.

ing substantially equal.

chamber having vertically spaced openings leading therefrom andcommunicating with the outside atmosphere and means within the innerwall cooling the same to the ldewpoint temperature of the outsideatmosphere and thereby causing air from t-he outside atmosphere normallyto ,circulate downwardl through the chamber, said openings exten ingacross the chamber for substan- 9. In a device'of the characterdescribed, for preventing the condensation of moisture on Xthe `exteriorof a refrigerator cabinet, the combination of inner and outer wallsspaced apart with an intervening air chamber, the chamber havingvertically spaced openings leading therefrom and communieating with theoutside atmosphere, means within the inner wall for cooling the same tothe dew-point temperature of the outside atmosphere and thereby causingair from the outside atmosphere to circulate downwardly through thechamber, and means for collecting moisture condensed` on the outersurface` of the inner Wall.

l0. In adevice of the character described, for preventing thecondensation ofmoisture on the exterior of a refrigerator cabinet, thecombination of an inner refrigerating compartment, a casing surroundingthe same and vproviding an intervening air chamber out loutsideatmosphere and thereby causing air from the outside atmosphere normallyto circulate downwardly through the air chamber.

11. In a device of the character described, for preventing thecondensation of moisture on the exterior of a refrigerator cabinet,

the combination of an inner refrigerating compartment, a casingsurrounding the same and providing'an intervening air chamber out ofcommunication with said compartment, said casing being formed .withopenings leading from the chamber adjacentthe `upper and lower endsthereof and communieating with the outside atmosphere, means within saidcompartment for cooling the wall thereof to the dew-point of the`outside atmosphere and thereby causing air from the outside atmosphereto circulate down-v wardly through the air chamber, and means forcollecting moisture condensed on lthe outersurface of the wall of thecompart- 125 ment. y

12. In a device of the character described,

for preventing the condensation of moisture 'on the exterior of arefrlgerator cabinet, the. comblnation of an mner 4refrigerating 130compartment, a casing surrounding the same and providing intervening airchambers, and a door comprlslng inner and outer Walls 'spaced apart withan intervening air chamon the exterior of a refrigerator cabinet,`

the combinationof an inner refrigerating compartment, a casingsurrounding the same and providing an intervening air chamber, a doorcomprising 'inner and outerwalls spaced apart with an intervening airchamber, each of said chambers being out of com-I munication with therefrigerating compartment and being formed with vertically spacedopenings communicating with the outside atmosphere, and means within therefrigerating compartment for cooling the same to the 'dew-pointtemperature of the outside atmosphereand thereby causingjair from theoutside atmosphere vto vcirculate downwardly through the respectivechambers. 4

14.-. In a device of the character described,

for preventing the condensation of moisture on the exterior of arefrigerator cabinet,

the combination of an inner refrigerating compartn'ient, a casingsurrounding the same and 'providingan intervening air chamber, a doorcomprising linner and outer walls spaced apart with an intervening airchamber, each of said chambers being out of communication with therefrigerating compartment and being formed with vertically spacedopenings communicating with the outside atmosphere, means within therefrigerating compartment for' cooling the same to the dew-pointtemperature of the outside atmosphere and thereby causing air from theoutside atmosphere to circulate downwardly through the respectivechambers, and coml men means for collecting moisture condens-1 ing on*the outer surface of the wall of the compartment and on't-he outersurface of the inner Wall of the door. n

15. In a device of the character described, for preventing condensationon the exterior of a refrigerator cabinet, the combination of a doorcomprising. inner and outer Walls spaced apart with an intervening airchamber, the chamber having vertically spaced openings communicatingwith the outside atmosphere, means within the inner wall for cooling thesame vto the dew-point temperature of the outside atmosphere and therebycausing air from the outside atmosphere to circulate downwardly throughsaid 'chamber, and means for collecting moisture condensed on the outersurface o? the inner wall.

In testimony whereof, I have signed my name to this specification.

ALBERT I.. LAMBERT.

